Welcome to "Croissant Curl Reader", a 4th Grade Angles mission at the Explorer (core) level, staged in our bakery scenario. The mission opens with a hands-on prompt: "Use the protractor: rotate the orange ray to align with the blue target. What angle is shown?" You'll reason about the numbers 110, 180 across 3 guided steps.
Behind the bakery story, this lesson is really about angles aligned to CCSS 4.MD.C.6. Measure angles in whole-number degrees using a protractor. The key strategy this mission asks you to internalise: 70 is the supplement.
A general pattern to watch for in 4th Grade angles — illustrated with example numbers below, which may differ from this lesson's: Reading the wrong scale (e.g., calling a 60° angle "120°"). Always start at the 0° mark of the scale that runs along your first ray. The number that ray points to should read 0. If you get stuck on "Croissant Curl Reader", the adaptive Socratic hints below escalate from a gentle nudge to a worked-out strategy — the same way a one-on-one tutor would coach you through it.
Grade 4 · Angles
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] Use the protractor: rotate the orange ray to align with the blue target. What angle is shown?
1
Active StepRotate the orange ray to align with the blue target at 110°.
Everything you need to know about the Socratic experience.
Use the protractor: rotate the orange ray to align with the blue target. What angle is shown? Hint: Align the orange ray with the blue target by tapping + or −. Read the inner scale.
An angle of 110° is classified as: If you get stuck, the adaptive hint is: 110° is obtuse.
Explorer missions hit the core abstraction at typical numeric ranges — this is where conceptual mastery is built. Within 4th Grade Angles, expect numbers in the corresponding range.
Misaligning the vertex with the protractor centre. The vertex MUST sit on the protractor's small centre dot. Even a small slip changes the reading.
Anglesum (Once you can measure, you can decompose: total angle = sum of parts.). Open /grade-4/anglesum to start that topic's missions.
Yes. Every mission, handbook page, and topic hub is mapped to a specific CCSS code (visible in the page header). The curriculum follows the CCSS coherence map: Grade 1 number sense → Grade 3 multiplicative thinking → Grade 6 ratio reasoning, with each grade building strictly on the prior year's foundations.
Socratic teaching answers a question with a better question. Instead of "the answer is 12", the system asks "if you had 3 groups of 4, how could you skip-count?" The goal is to externalize the learner's reasoning so they hear themselves think. Every Inquiry AI hint follows this pattern: nudge → reframe → analogy → only then a worked example, in that order.
